Python – Pair with Maximum product

Sometimes, we need to find the specific problem of getting the pair which yields the maximum product, this can be computed by getting initial two elements after sorting. But in some case, we don’t with to change the ordering of list and perform some operation in the similar list without using extra space. Let’s discuss certain ways in which this can be performed.

Method #1 : Using list comprehension + max() + combination() + lambda
This particular task can be performed using the combination of above functions in which we use list comprehension to bind all the functionalities and max function to get the maximum prod, combination function finds all prods internally and lambda function is used to compute the product.

# Python3 code to demonstrate
# Pair with Maximum product
# using list comprehension + max() + combinations() + lambda
from itertools import combinations

# initializing list
test_list = [3, 4, 1, 7, 9, 1]

# printing original list
print("The original list : " + str(test_list))

# using list comprehension + max() + combinations() + lambda
# Pair with Maximum product
res = max(combinations(test_list, 2), key = lambda sub: abs(sub[0] * sub[1]))

# print result
print("The maximum product pair is : " + str(res))

Output :

The original list : [3, 4, 1, 7, 9, 1]
The maximum product pair is : (7, 9)

Method #2 : Using list comprehension + nlargest() + combination() + lambda
This method has potential of not only finding a single maximum but also k maximum product pairs if required and uses nlargest function instead of max function to achieve this functionality.

# Python3 code to demonstrate
# Pair with Maximum product
# using list comprehension + nlargest() + combinations() + lambda
from itertools import combinations
from heapq import nlargest

# initializing list
test_list = [3, 4, 1, 7, 9, 8]

# printing original list
print("The original list : " + str(test_list))

# using list comprehension + nlargest() + combinations() + lambda
# Pair with Maximum product
# computes 2 max product pair
res = nlargest(2, combinations(test_list, 2), key = lambda sub: abs(sub[0] * sub[1]))

# print result
print("The maximum product pair is : " + str(res))

Output :

The original list : [3, 4, 1, 7, 9, 8]
The maximum product pair is : [(9, 8), (7, 9)]